Fix helper

Author: BoRuDar

configurator.go

@@ -14,6 +14,7 @@ func New[T any](
 		configPtr:           new(T),
 		providers:           providers,
 		registeredProviders: map[string]struct{}{},
+		registeredTags:      map[string]struct{}{},
 	}
 
 	return cfg.initValues()
@@ -22,6 +23,7 @@ func New[T any](
 type Configurator[T any] struct {
 	configPtr           *T
 	providers           []Provider
+	registeredTags      map[string]struct{}
 	registeredProviders map[string]struct{}
 }
 
@@ -42,6 +44,11 @@ func (c *Configurator[T]) initValues() (*T, error) {
 		}
 		c.registeredProviders[p.Name()] = struct{}{}
 
+		if _, ok := c.registeredTags[p.Tag()]; ok {
+			return nil, ErrProviderTagCollision
+		}
+		c.registeredTags[p.Tag()] = struct{}{}
+
 		if err := p.Init(c.configPtr); err != nil {
 			return nil, fmt.Errorf("cannot init [%s] provider: %w", p.Name(), err)
 		}
@@ -100,7 +107,7 @@ func (c *Configurator[T]) applyProviders(field reflect.StructField, v reflect.Va
 	}
 
 	for _, provider := range c.providers {
-		if _, found := fetchTagKey(field.Tag)[provider.Tag()]; !found {
+		if _, found := fetchTagKey(field.Tag, c.registeredTags)[provider.Tag()]; !found {
 			// skip provider if it's not specified in tags
 			continue
 		}

errors.go

@@ -12,4 +12,5 @@ var (
 	ErrInvalidInput          = errors.New("invalid input")
 	ErrNoProviders           = errors.New("no providers")
 	ErrProviderNameCollision = errors.New("provider name collision")
+	ErrProviderTagCollision  = errors.New("provider tag collision")
 )

helper.go

@@ -2,23 +2,15 @@ package configuration
 
 import (
 	"reflect"
-	"strings"
 )
 
-func fetchTagKey(t reflect.StructTag) map[string]struct{} {
+func fetchTagKey(t reflect.StructTag, registered map[string]struct{}) map[string]struct{} {
 	keys := map[string]struct{}{}
 
-	pairs := strings.Split(string(t), " ")
-	if len(pairs) == 1 && pairs[0] == "" {
-		return keys
-	}
-
-	for _, pair := range pairs {
-		kv := strings.Split(pair, `:"`)
-		if len(kv) < 1 {
-			return keys
+	for rt := range registered {
+		if _, ok := t.Lookup(rt); ok {
+			keys[rt] = struct{}{}
 		}
-		keys[kv[0]] = struct{}{}
 	}
 
 	return keys

helper_test.go

@@ -8,6 +8,13 @@ import (
 func Test_fetchTagKey(t *testing.T) {
 	t.Parallel()
 
+	registredTags := map[string]struct{}{
+		"json":    {},
+		"xml":     {},
+		"flag":    {},
+		"default": {},
+	}
+
 	tests := []struct {
 		name string
 		in   reflect.StructTag
@@ -27,9 +34,9 @@ func Test_fetchTagKey(t *testing.T) {
 		},
 		{
 			name: "non-empty tag value",
-			in:   reflect.StructTag(`json:"id"`),
+			in:   reflect.StructTag(`default:"one;two"`),
 			want: map[string]struct{}{
-				"json": {},
+				"default": {},
 			},
 		},
 		{
@@ -40,14 +47,35 @@ func Test_fetchTagKey(t *testing.T) {
 				"xml":  {},
 			},
 		},
+		{
+			name: "malformed tag",
+			in:   reflect.StructTag(`json`),
+			want: map[string]struct{}{},
+		},
+		{
+			name: "tag with spaces in value",
+			in:   reflect.StructTag(`flag:"name_flag||Some description" json:"id" xml:"ID"`),
+			want: map[string]struct{}{
+				"flag": {},
+				"json": {},
+				"xml":  {},
+			},
+		},
+		{
+			name: "special characters in tag value",
+			in:   reflect.StructTag(`default:"one;two-three_1,/ and this!=2*7&^3:,.	$"`),
+			want: map[string]struct{}{
+				"default": {},
+			},
+		},
 	}
 	for _, tt := range tests {
 		tt := tt
 
 		t.Run(tt.name, func(t *testing.T) {
 			t.Parallel()
 
-			assert(t, tt.want, fetchTagKey(tt.in))
+			assert(t, tt.want, fetchTagKey(tt.in, registredTags))
 		})
 	}
 }